Patients report permanent vision loss linked to GLP-1 weight-loss drugs

A growing wave of lawsuits is targeting the makers of blockbuster GLP-1 weight-loss drugs, with patients alleging that medications including Ozempic, Wegovy, and Mounjaro caused sudden and permanent vision loss. The litigation, consolidated into a federal multidistrict proceeding, centers on a condition known as nonarteritic anterior ischemic optic neuropathy, or NAION — an "eye stroke" that can leave patients blind in one or both eyes.

Mounting Legal Action

As of September 2026, 216 active cases are pending in the NAION-specific multidistrict litigation (MDL 3163), while the broader GLP-1 litigation — encompassing gastrointestinal injuries — has surpassed 4,000 cases filed against manufacturers since 2023. The defendants include Novo Nordisk ↗ 4.95%, which manufactures Ozempic and Wegovy, and Eli Lilly ↗ 0.61%, the maker of Mounjaro and Zepbound. Plaintiffs allege the companies failed to adequately warn patients and physicians about the risk of serious eye injuries.telegraph+3

A federal court held a "Science Day" hearing on June 2, 2026, where both sides presented evidence on the link between GLP-1 drugs and NAION, and a Rule 702 hearing on the admissibility of expert witnesses took place earlier this month.seegerweiss+1

The Medical Evidence

NAION occurs when blood flow to the optic nerve is blocked, causing rapid and often irreversible damage. A key study found that patients on semaglutide faced a roughly fourfold increased risk of developing the condition compared with those on other diabetes medications. The European Medicines Agency concluded last year that NAION should be listed as a possible side effect of semaglutide, estimating it may affect up to one in 10,000 users.levinlaw+2

The Wall Street Journal News Corp ↗ 4.15% reported Saturday on the case of Michelle Fennell, 53, who lost peripheral vision after developing NAION. In the United Kingdom, The Telegraph profiled Diana Pardoe, 60, and Dominique Willison, 46, both left blind in one eye after taking Wegovy. "If I'd known what I know now, I would never have started on them," Pardoe said.wsj+1

Wider Safety Concerns

The vision-loss lawsuits come amid broader scrutiny of GLP-1 side effects. In the UK, regulators have received more than 150,000 adverse-reaction reports and 216 suspected death reports linked to the drugs, according to data from the MHRA and the British Medical Journal. Separately, a Mirror investigation published Saturday found that online pharmacies are failing to properly verify patients before prescribing Wegovy tablets, with AI-altered photos allowing underweight individuals to obtain the medication.mirror+1

Both Novo Nordisk and Eli Lilly have said patient safety remains their priority and that side effects are detailed in their product documentation.telegraph